I had one interviewer in a screening interview tell me he was "calling me back" and that he would "really like for [me] to come back and talk to other attorneys about working at [firm] this summer." Two weeks later, thanks but no thanks letter in the mail.

On another screening interview, the guy told me he was "recommending [me] for a call back interview." Three weeks later, thanks but no thanks. I felt this wasn't as bad since it seemed like he was saying he was putting in a good word, but there were no guarantees.

On a callback interview, the leader of the practice group where I will end up told me: "We really need people with your background, I hope that you accept our offer and I look forward to working with you next summer." Two weeks later, thanks but no thanks ...

Moral of the story: the person you are talking to doesn't always make the decision. So even if they really wanted you there, it doesn't mean you will get an offer/callback. You never know until you get the offer.

Also, keep in mind that callback offers don't come right away. So you I wouldn't fret yet. I also wouldn't count on it either.

From my understanding the person you meet with is not always the one who actually makes the hires, in many cases especially big firms with formal student programs, they have committess that make collective choices.